Salehi: Iran will never hesitate to strike back

Iran will not "hesitate to strike back when necessary", as it has done before, said the the head of the country's nuclear agency on Monday.

Speaking at a meeting of the International Atomic Energy Agency (IAEA) in Vienna, Ali Akbar Salehi accused the US of "inflicting harm" on people across the Middle East.

Salehi also decried the targeted killing of Iranian general Qassem Soleimani last month in a US airstrike, who he said was Iran's "most instrumental element" in fighting Islamic State.

When US Secretary of Energy Dan Brouillette stood behind the podium, he delivered countering remarks and urged Tehran to allow IAEA monitoring of its nuclear facilities.

"It is imperative that Iran provide full and timely cooperation to explain the presence of uranium particles at an undeclared location. As the IAEA has reported, time is of the essence," he said.